Site-Selective Occupancy of Eu2+ Toward Blue-Light-Excited Red Emission in a Rb3 YSi2 O7 :Eu Phosphor

Jianwei Qiao; Lixin Ning; Maxim S Molokeev; Yu-Chun Chuang; Qinyuan Zhang; Kenneth R Poeppelmeier; Zhiguo Xia

doi:10.1002/anie.201905787

Site-Selective Occupancy of Eu²⁺ Toward Blue-Light-Excited Red Emission in a Rb₃ YSi₂ O₇ :Eu Phosphor

Angew Chem Int Ed Engl. 2019 Aug 12;58(33):11521-11526. doi: 10.1002/anie.201905787. Epub 2019 Jul 2.

Authors

Jianwei Qiao¹, Lixin Ning², Maxim S Molokeev^{3

4

5}, Yu-Chun Chuang⁶, Qinyuan Zhang⁷, Kenneth R Poeppelmeier⁸, Zhiguo Xia^{1

7}

Affiliations

¹ School of Materials Sciences and Engineering, University of Science and Technology Beijing, Beijing, 100083, P. R. China.
² Anhui Key Laboratory of Optoelectric Materials Science and Technology, Key Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Normal University, Wuhu, 241000, China.
³ Laboratory of Crystal Physics, Kirensky Institute of Physics, Federal Research Center KSC SB RAS, Krasnoyarsk, 660036, Russia.
⁴ Siberian Federal University, Krasnoyarsk, 660041, Russia.
⁵ Department of Physics, Far Eastern State Transport University, Khabarovsk, 680021, Russia.
⁶ National Synchrotron Radiation Research Center, Hsinchu, 300, Taiwan.
⁷ State Key Laboratory of Luminescent Materials and Devices and Institute of Optical Communication Materials, South China University of Technology, Guangzhou, 510641, China.
⁸ Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208-3113, USA.

PMID: 31167043
DOI: 10.1002/anie.201905787

Abstract

Establishing an effective design principle in solid-state materials for a blue-light-excited Eu²⁺ -doped red-emitting oxide-based phosphors remains one of the significant challenges for white light-emitting diodes (WLEDs). Selective occupation of Eu²⁺ in inorganic polyhedra with small coordination numbers results in broad-band red emission as a result of enhanced crystal-field splitting of 5d levels. Rb₃ YSi₂ O₇ :Eu exhibits a broad emission band at λ_max =622 nm under 450 nm excitation, and structural analysis and DFT calculations support the concept that Eu²⁺ ions preferably occupy RbO₆ and YO₆ polyhedra and show the characteristic red emission band of Eu²⁺ . The excellent thermal quenching resistance, high color-rendering index R_a (93), and low CCT (4013 K) of the WLEDs clearly demonstrate that site engineering of rare-earth phosphors is an effective strategy to target tailored optical performance.

Keywords: light-emitting diodes; red-emitting phosphors; silicates; site occupancy.

Publication types

Review

Grants and funding

51722202/National Natural Science Foundation of China